Game perofrmance on Thunderbolt Display vs. MacBook
I have noticed that on several games there are some performance issues when connecting a Thunderbolt Display.
The game runs great on the MacBook display itself, but as soon as it runs on the Thunderbolt Display, performance is poor.
In general FPS drops by 50% and the game can become unresponsive. Rebooting the MacBook does not make a difference.
Example game: Cities Skylines (v1.0.7c)
But there are several games made by several developers that have exactly the same issue.
System:
MacBook Pro (Retina, Mid 2012)
2.3 GHz Intel Core i7
8 GB 1600 MHz DDR3
NVIDIA GeForce GT 650M 1024 MB
OSX 10.10.3
15.4 Inch display (2880x1800) - RETINA
Apple Thunderbolt Display 2560x1440 - NON RETINA
Symptoms:
Game boots, runs without any problem.
Game runs very well on native MacBook display.
Game runs poor on external ThunderBolt display at lower resolution.
Situation 1: without external display
- Runs VERY smooth on MacBook on native display at 1440x900.
- High detail enabled, very high FPS. Looks great!
Situation 2: with external display
- Runs ok at 1280x720 on Thunderbolt Display.
- Must lower detail to have reasonable FPS, looks terrible.
Possible fixes:
It has been suggested to use the MacBook in clamshell mode (closed lid) so that only one screen has to rendered.
This has very limited impact on the actual performance of the game.
MacBook Pro (Retina, Mid 2012), OS X Yosemite (10.10.3), Apple Thunderbolt Display FW 26.2